[NOT TO COMMIT!] Replace third_party/tcmalloc/chromium with tcmalloc r136 (the latest).

third_party/tcmalloc/chromium/src/system-alloc.h

 // Copyright (c) 2005, Google Inc.
 // All rights reserved.
 // 
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 // 
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 53 matching lines @@
 // contained in the specified range of memory will not be used for a
 // while, and can be released for use by other processes or the OS.
 // Pages which are released in this way may be destroyed (zeroed) by
 // the OS.  The benefit of this function is that it frees memory for
 // use by the system, the cost is that the pages are faulted back into
 // the address space next time they are touched, which can impact
 // performance.  (Only pages fully covered by the memory region will
 // be released, partial pages will not.)
 extern void TCMalloc_SystemRelease(void* start, size_t length);
 
-// Called to ressurect memory which has been previously released
-// to the system via TCMalloc_SystemRelease.  An attempt to
-// commit a page that is already committed does not cause this
-// function to fail.
-extern void TCMalloc_SystemCommit(void* start, size_t length);
-
-// Guards the first page in the supplied range of memory and returns the size
-// of the guard page. Will return 0 if a guard cannot be added to the page
-// (e.g. start is not aligned or size is not large enough).
-extern size_t TCMalloc_SystemAddGuard(void* start, size_t size);
-
 // The current system allocator.
 extern PERFTOOLS_DLL_DECL SysAllocator* sys_alloc;
 
 #endif /* TCMALLOC_SYSTEM_ALLOC_H_ */